Generate toFooElement() functions from tagname data

Source/core/html/HTMLTextAreaElement.h

Index: Source/core/html/HTMLTextAreaElement.h
diff --git a/Source/core/html/HTMLTextAreaElement.h b/Source/core/html/HTMLTextAreaElement.h
index d415cc31b57fe5354c0e6585b7bb4effa49a7578..557d99863003739c66aba82846e217bfd2d4b5d1 100644
--- a/Source/core/html/HTMLTextAreaElement.h
+++ b/Source/core/html/HTMLTextAreaElement.h
@@ -137,12 +137,6 @@ inline bool isHTMLTextAreaElement(const Element* element)
     return element->hasTagName(HTMLNames::textareaTag);
 }
 
-inline HTMLTextAreaElement* toHTMLTextAreaElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || isHTMLTextAreaElement(node));
-    return static_cast<HTMLTextAreaElement*>(node);
-}
-
 } //namespace
 
 #endif